diff --git a/basis/cpu/ppc/linux/linux.factor b/basis/cpu/ppc/linux/linux.factor
index c6649c7ad2..090495aa11 100644
--- a/basis/cpu/ppc/linux/linux.factor
+++ b/basis/cpu/ppc/linux/linux.factor
@@ -1,6 +1,7 @@
 ! Copyright (C) 2008 Slava Pestov.
 ! See http://factorcode.org/license.txt for BSD license.
-USING: accessors system kernel alien.c-types cpu.architecture cpu.ppc ;
+USING: accessors system kernel layouts
+alien.c-types cpu.architecture cpu.ppc ;
 IN: cpu.ppc.linux
 
 <<
@@ -8,11 +9,11 @@ t "longlong" c-type (>>stack-align?)
 t "ulonglong" c-type (>>stack-align?)
 >>
 
-M: linux reserved-area-size 2 ;
+M: linux reserved-area-size 2 cells ;
 
-M: linux lr-save 1 ;
+M: linux lr-save 1 cells ;
 
-M: float-regs param-regs { 1 2 3 4 5 6 7 8 } ;
+M: float-regs param-regs drop { 1 2 3 4 5 6 7 8 } ;
 
 M: ppc value-structs? f ;
 
diff --git a/basis/cpu/ppc/macosx/macosx.factor b/basis/cpu/ppc/macosx/macosx.factor
index bb607d0e44..877fb37d31 100644
--- a/basis/cpu/ppc/macosx/macosx.factor
+++ b/basis/cpu/ppc/macosx/macosx.factor
@@ -1,6 +1,7 @@
 ! Copyright (C) 2008 Slava Pestov.
 ! See http://factorcode.org/license.txt for BSD license.
-USING: accessors system kernel alien.c-types cpu.architecture cpu.ppc ;
+USING: accessors system kernel layouts
+alien.c-types cpu.architecture cpu.ppc ;
 IN: cpu.ppc.macosx
 
 <<
@@ -9,11 +10,11 @@ IN: cpu.ppc.macosx
 4 "double" c-type (>>align)
 >>
 
-M: macosx reserved-area-size 6 ;
+M: macosx reserved-area-size 6 cells ;
 
-M: macosx lr-save 2 ;
+M: macosx lr-save 2 cells ;
 
-M: float-regs param-regs { 1 2 3 4 5 6 7 8 9 10 11 12 13 } ;
+M: float-regs param-regs drop { 1 2 3 4 5 6 7 8 9 10 11 12 13 } ;
 
 M: ppc value-structs? t ;
 
diff --git a/basis/cpu/ppc/ppc.factor b/basis/cpu/ppc/ppc.factor
index d2d1e26396..2be46d15ee 100644
--- a/basis/cpu/ppc/ppc.factor
+++ b/basis/cpu/ppc/ppc.factor
@@ -349,12 +349,17 @@ M: ppc %gc
     "end" resolve-label ;
 
 M: ppc %prologue ( n -- )
-    0 scratch-reg LOAD32 rc-absolute-ppc-2/2 rel-this
+    #! We use a volatile register (r11) here for scratch. Because
+    #! callback bodies have a prologue too, we cannot assume
+    #! that c_to_factor saved all non-volatile registers, so
+    #! we have to respect the C calling convention. Also, we
+    #! cannot touch any param-regs either.
+    0 11 LOAD32 rc-absolute-ppc-2/2 rel-this
     0 MFLR
     1 1 pick neg ADDI
-    scratch-reg 1 pick xt-save STW
-    dup scratch-reg LI
-    scratch-reg 1 pick next-save STW
+    11 1 pick xt-save STW
+    dup 11 LI
+    11 1 pick next-save STW
     0 1 rot lr-save + STW ;
 
 M: ppc %epilogue ( n -- )
diff --git a/build-support/factor.sh b/build-support/factor.sh
index 7fbb54a568..bd234afb5f 100755
--- a/build-support/factor.sh
+++ b/build-support/factor.sh
@@ -271,17 +271,21 @@ check_os_arch_word() {
 
 set_build_info() {
     check_os_arch_word
-    MAKE_TARGET=$OS-$ARCH-$WORD
     if [[ $OS == macosx && $ARCH == ppc ]] ; then
         MAKE_IMAGE_TARGET=macosx-ppc
+        MAKE_TARGET=macosx-ppc
     elif [[ $OS == linux && $ARCH == ppc ]] ; then
         MAKE_IMAGE_TARGET=linux-ppc
+        MAKE_TARGET=linux-ppc
     elif [[ $OS == winnt && $ARCH == x86 && $WORD == 64 ]] ; then
         MAKE_IMAGE_TARGET=winnt-x86.64
+        MAKE_TARGET=winnt-x86-64
     elif [[ $ARCH == x86 && $WORD == 64 ]] ; then
         MAKE_IMAGE_TARGET=unix-x86.64
-	else
+        MAKE_TARGET=$OS-x86-64
+    else
         MAKE_IMAGE_TARGET=$ARCH.$WORD
+        MAKE_TARGET=$OS-$ARCH-$WORD
     fi
     BOOT_IMAGE=boot.$MAKE_IMAGE_TARGET.image
 }
diff --git a/vm/callstack.c b/vm/callstack.c
index c9466bbbb2..b7e99b418c 100755
--- a/vm/callstack.c
+++ b/vm/callstack.c
@@ -117,7 +117,7 @@ CELL frame_executing(F_STACK_FRAME *frame)
 F_STACK_FRAME *frame_successor(F_STACK_FRAME *frame)
 {
 	if(frame->size == 0)
-		critical_error("Stack frame has zero size",frame);
+		critical_error("Stack frame has zero size",(CELL)frame);
 	return (F_STACK_FRAME *)((CELL)frame - frame->size);
 }
 
diff --git a/vm/cpu-x86.32.S b/vm/cpu-x86.32.S
index eec850dc9e..6ddbd52da2 100755
--- a/vm/cpu-x86.32.S
+++ b/vm/cpu-x86.32.S
@@ -10,7 +10,7 @@ and the callstack top is passed in EDX */
 #define DS_REG %esi
 #define RETURN_REG %eax
 
-#define NV_TEMP_REG %rbx
+#define NV_TEMP_REG %ebx
 
 #define CELL_SIZE 4
 #define STACK_PADDING 12